Does the fluid flow from the bottom of the radiator up to the top and then into the engine or is it the other way around?

 

 

Flows from top to bottom - top is the pressure side and the bottom is the suction.

 

Other way around. When the thermostat opens it lets the fluid flow into the top of the radiator. It flows down through the rad and into the water pump which sends it back through the engine.

 

Thanks, you guys are awesome!

 

Simple convection.

As the coolant cools in the rad, it'll naturally sink to the bottom, while the hottest collant rises to the top.

By drawing coolant from the bottom of the rad, designers ensure the coolest coolant in the system is pumped into the engine passages.

 

Also, if the coolant is a little low one might draw air in at the top, therefore the bottom is used to feed the engine because any coolant at all will gravitate there.

Touch the hoses when the engine is warm. the top hose will be noticeably hotter than the bottom hose. That's why the top hose gives out first: it deteriorates under the extreme heat, while the bottom hose lasts until you cut it off. Pays to carry an extra top hose in your bins or on top the spare tire. Along with an extra heater hose. Either one of those lets go and it dumps your coolant pronto on the pavement, your engine overheats and the seals are ruined.

B